Brake



Sept. 25, 1945. o. RASMUSSEN BRAKE Filed NOV. L0, 1944 I5 Sheets-Sheet l Sept. 25, 1945. I o. RASMUSSEN BRAKE Filed Nov. 10, 194 5 Sheets-Sheet 2 l'mnentor (924/.Fas77221ss9n M (Ittoruegs Sept. 25, 1945. o. RASMUSSEN 2,385,540

BRAKE Filed Nov. 10, 1944 s Sheets-Sheet 3 Zhwentor u W r Gttomcgs Patented Sept. 25, 1945 C UNITED STATES PATENT OFFICE BRAKE Olaf Rasmussen. Sidney. Ohio. assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application November 10, 1944, Serial No. 562,794 7 Claims. (Cl. 188-78) This invention aims to provide a better brake lining becomes worn. A somewhat U-shaped for vehicles. spring 4| anchored in openings 43 in the shoe An object of the invention is to utilize as comparts near the wheel cylinder restores the parts pletely as possible the available annular surface after being spread in the act of applying the of a wheel carried drum. Another object is to brake. By reference to Fig. 5 there will be seen lessen the applying effort by taking full advanan elongated recess 45 in tube 25 of the anchor tage of the drum rotation to apply the brake platelil to accommodate the wheel cylinder. A shoes to the drum. The arrangement involves similar cutaway region 41 is provided for the admultiple shoe assemblies, the spreading of one justing mechanism 39. Brake shoes 3| and 33 oi! which against the drum renders it a servo shoe at the sides of shoe 29 may be in the iorm of conoperable to apply the others whereby relatively tinuous bands broken only in the region where low rubbing speed between lining and drum is they are applied and anchored. The anchor cyleifective to check drum rotation. Another adinder l3 has two pairs of circumferentially spaced vantage resides in the less frequent need of adslots marked 5|, 53 and 55, 51. Slots 5| and 53 justment by providing the adjustment on the receive lugs 59 and SI of shoe 3| and slots 55 and servo shoe which does less of the braking. Less 51 receive similar lugs on the web of shoe 33. A

drum expansion will be caused because of less U-shaped spring 63 serves to hold these lugs in heat, and better dissipation of heat is provided abutment with the ends of the slots as shown than in the more conventional wheel brakes. by Fig. 3. Projecting between the adjacent ends Qther objects and advantages will be apparent of these side shoes are trunnions 65 and 31 on from a reading of the following description. the whieel cylinder. They are suitably notched On the drawings, Fig. 1 is a view in transverse to engage the shoe webs as shown in Fig. 2. section of the novel brake as applied to a drum Trunnion G5 is provided with passages 59 and carried by a vehicle wheel. Fig. 2 is a section 1|, the former to afford communication between through e pp means. F g. 3 is a view in the fluid supply pipe 13 and the cylinder 33 and elevation and p rtly in section showing the brake the latter for freeing the cylinder of air. A flexas seen from line 3-3 of Fig. 2. Fig. 4 is a view ible boot may be used as shown at 15. in elevation of the servo shoe assembly and Fig. 5 The operation may be briefly described. When is a detail view of an anchorage member. fluid is forced into the wheel cylinder the shoe 2! Referring to the drawings for a more complete engages the rotating drum and tends to rotate description, numeral 1 is intended to represent with it since the shoe is not anchored and the an axle, a art or the wheel being indicated by cylinder is floating. Its trunnions then move one e brake d carried y e wheel and or the other of the ends or the secondary shoes axle is marked A fixed axle housing is seen a d thereby tend to carry around the secondary at I3. To it is secured by welding or otherwise h e However, the end or each secondary shoe 8. shouldered annulus |5 to which is secured as opposite the end pushed by the trunnion is any fastening a s 11 a anchor plate A chored on the anchor plate. H.101- example, and guard 1| m y be used between Part5 and its referring to Fig. 3, trunnion 61 moves clockwise fla 23 overlying the drum This anchor the end lug 58 is pushed of! its anchor at the end plate is shown in perspective in a 5. It is of slot 5| but the end of slot 53 stops lug 8|. formed as a tube 25 with a flange 21 the latter be- Th anchoring f th side shoes obviously stops ing the part secured to the annulus l5 as stated the rotation f the intermediate shoe. above. The multiple shoe assembly includes The brake mechanism therefore uses to the three shoes, an intermediate shoe marked 29 and greatest advantage the whole drum surface. side shoes marked 3| and 33. The webs of these Ther i les wear o the servo shoe than on the shoes rest on the ancho tu e 5. side shoes so that there is less occasion for ad- A cylinder 35 and piston 31 are located bejustment.

tween one pair of ends of the central shoe 19, I claim:

the cylinder and piston being notched as seen 1. In a brake, a drum, shoes arranged side-byby Fig. 2 to engage the webs of the shoe parts. side in parallel planes and operable to engage the This spreading means is floating and not andrum, means to spread an intermediate one of chored as in the usual form of hydraulic brakes. said shoes int dru contact, means whereby Between the opposite ends of the shoe parts the movement of said intermediate shoe by conthere is shown a conventional adjusting means tact with the drum expands other shoes one on markfid 39 to spread apart these ends when e each side of said intermediate" shoe, means to anchor one end of each of said side shoes, both side shoes being expanded substantially simultaneously whereby all three shoes are anchored and take part in retarding drum rotation c 2. In a brake, a fixed brake anchor having a tubular part, a wheel carried drum surrounding said anchor, three brake shoes arranged side by side between the drum and the anchor tube, means to spread the intermediate shoe into drum contact, means responsive to rotary movement of said intermediate shoe with the drum to actuate the shoes on each side of the intermediate shoe, anchor means for end; parts of each of said side shoes, both side shoes being actuated substantially simultaneously whereby all three shoes cooperate in retarding drum rotation.

3. The invention defined by claim 2, said anchor having a plurality of slots and said side shoes having radial lugs extending within said slots and adapted to anchor on the ends thereof. 1

4. In a brake, a relatively fixed member, a rotatable drum, an anchor having a tube coaxially arranged within the drum and secured to the fixed member, an intermediate shoe and side shoes having webs supported by said tube, means between the ends of said intermediate shoe to expand said shoe into contact with the drum to rotate therewith, lug and slot formations associated with said side shoes and tube to limit rotation of said side shoes and means associated with said expanding means and responsive to its rotary movement to spread said side shoes against the drum,

5. The invention defined by claim 4, said lug and slot means being provided .at each end of each side shoe to facilitate braking in both directions of drum rotation.

6. The invention defined by claim 4, said relatively fixed member being an axle housing coaxial with and within said anchor.

7. The invention defined by claim 4, said expanding means being a hydraulic wheel cylinder and said last named means being trunnions extending laterally from said cylinder into the space between the ends of the side brake shoes.

OLAF' RASMUSSEN. 

